Starting a One Piece collection

First pick a goal: a set, a character, or the cards you find beautiful. Open a few boosters for fun, but buy the specific cards you want as singles: it's often much cheaper. Put them in sleeves and a binder right away, and keep track of what you have so you know what's missing.

Boosters for the surprise, singles to get a specific card: it's usually much cheaper than opening boosters hoping to pull it.

There's no minimum: many cards are worth less than a euro. Set yourself a monthly amount, and keep some for sleeves and a binder.

The one whose artwork you like, or the latest, still easy to find in shops. Each set's list, with its card prices, is on gotem.

Both are collected. Japanese cards usually come out earlier and have their own value; French cards can be read and played in France. Pick one language per goal, it's simpler.

Add your cards to gotem. (or scan them): their market value shows, by language and condition, and updates every day.

Buy in shops or from well-rated sellers, compare with the market price, and look at the card closely: print, colours, texture. An offer far below the market price should put you on alert.